1. Field of the Invention
The present invention relates to a technique to control printing and more particularly to a technique to control printing a plurality of copies.
2. Description of the Related Art
A print system is known which performs printing using a printing apparatus based on a raster image sent from a host computer. The host computer produces a raster image by performing a process described below. In the host computer, first, application software produces data such as characters, graphics, pictures, etc. The produced data is deployed in a virtual page memory by a printer driver running on the host computer. The data deployed in the page memory is subjected to a process such as a color conversion, halftone processing, etc., and the resultant data is transmitted as a printer command to a printer. Note that the application software is hereinafter referred to simply as the application.
In such a print system, a very large processing load is imposed on the host computer. In such a situation, a plurality of copies may be printed in such a manner, for example, as disclosed in Japanese Patent Laid-Open No. 6-202822. First, a printer command produced as a result of the process performed in printing of a first one of copies is stored in an auxiliary storage device such as a hard disk. When second and following ones of the plurality of copies are printed, the printer command stored in the auxiliary storage device is transmitted to the printer. However, if the data size of the printer command is greater than a free storage space of the auxiliary storage device, the printer command cannot be stored in the auxiliary storage device. In such a case, the printer command is stored in the auxiliary storage device only when the auxiliary storage device has a free storage space large enough to store one page of print data, but otherwise the printer command is not stored.
However, there is a tendency that an increasing number of documents are produced in the form of an electronic document, and each document tends to have an increasing number of pages. Furthermore, an increase in resolution of a printer causes an increase in the size of a printer command (print image data) per page. This results in an increase in the probability that printer commands of all pages cannot be stored in the auxiliary storage device. In such a case, printer commands of only part of the all pages are stored in the auxiliary storage device, and the remaining pages whose printer commands are not stored in the auxiliary storage device cannot be printed at a high speed in the printing process for second and following ones of the plurality of copies.
In the printing operation, the application and an operating system (hereinafter referred to simply as an OS) also use a large amount of memory space of the auxiliary storage device. Therefore, if all the free storage space of the auxiliary storage device is used to store the print data, the application or the OS becomes impossible to correctly operate or the system is brought into an unstable state.
A wide variety of systems have become available. In some systems, the auxiliary storage device does not have a free storage space large enough to store even one page of printer commands. For example, this can occur when printing is performed using a portable telephone or a game machine as a host computer. Most portable telephones or game machines used as a host computer do not have an auxiliary storage device, and thus printer commands are stored in a main memory of a host computer or a printer. However, the main memory has a very small free storage space. In many cases, even one page of printer commands cannot be stored in the main memory.
In recent years, a low-cost printer integrated with a scanner called a multifunction printer has become very popular. However, most such multifunction printers do not have an auxiliary storage device, and thus when a plurality of sets are copied directly from the scanner to the printer, printer commands are stored in a main memory of the multifunction printer because there is no other available memory space. However, in many cases, because of the small storage capacity of the main memory, even one page of printer commands cannot be stored.